In the near future(should be about year 2030 or maybe even earlier), all cars will use a new kind of energy source to replace petrol and diesel so that cars will be more environment-friendly and which option will you prefer? If what you have in mind is not in the poll, please specify other energy sources!

There's a car in a documentary that i watch a car can be powered by just air, so you don't have to pay for any bill, the car will suck in the surrounding air by itself to use as a fuel to move the car! Amazing!

electric and hydrogen are good in term of carbon emission. but they are not friendly for the environment at the end of their battery usage (highly toxicity).
bio diesel? making petrol from food? and look at those food price rises... plain dumb, the only one whose profited from bio diesel and such is the farmers.
solar power might be good choice, but the power generated as today is too little to be mass produced, give it another 10-20 year?

another way to helping reduce emission? ride a bike, use public transport, walk. at least until they found a better way.